3.1 About the Operating Systems

These are my personal views and not related to the views of the
Linux and/or OpenSolaris, or in general, the Open-Source community.

Linux:Linux is the kernel or core of an OS called GNU/Linux system, where the GNU Project provides the
software and applications that runs on the Linux kernel. The Linux kernel,
originally written by Linus Benedict Torvalds, is a UNIX-clone, which is POSIX
compliant and was initially targeted towards the Intel x86 architecture. As
rightly mentioned in the Linux Information Sheet by Michael K.
Johnson at http://www.tldp.org,
"Linux is a completely free
reimplementation of the POSIX specification, with SYSV and BSD
extensions (which means it looks like Unix, but does not come from the
same source code base), which is available in both source code and
binary form. Its copyright is owned by Linus Torvalds
<torvalds@transmeta.com> and other contributors, and is freely
redistributable under the terms of the GNU General Public License
(GPL)".

OpenSolaris:Linux powering a GNU/Linux system
is a good system, but is it the best? Probably no. And if the same query involves running a mission-critical real-time million dollar system,
probably "guaranteed" no for many years to come. Thus, we choose to
tread carefully into the realm of the 'big boys'; either SVR4 or BSD Unixes like HP Tru64 Unix, HP-UX, IBM-AIX and the ultimate commercial UNIX of all, Sun Microsystems' SOLARIS.
OpenSolaris is the open-source build of SOLARIS; with initial release
2008.11 meant for x86 platform and on June 1, 2009, OpenSolaris 2009.06
was released, with support for both the x86 and SPARC platforms.

The power of
Solaris comes from the 100% pre-emptive nature of its underlying kernel SunOS. The
SunOS architecture is way too complicated to
explain here in detail, but quintessentially speaking, one of the very
preliminary distinguishing feature that separates SunOS
kernel from Linux/FreeBSD/OpenBSD/NetBSD and other such OSes is
the killer real-time
multi-threading support that SunOS has for applications/binaries running on it. Solaris is the ONLY OS kernel on earth which
is 100% pre-emptive in nature, running not processes but threads in Kernel space
simultaneously and not alternatively; this technically speaking means, SunOS has a LWP threading model (see document link later on for details)
which maps a single user-space process with a single kernel-space
thread. Thus, SunOS kernel supports a real-time 1:1 scheduling
model wherein each application thread has its own LWP, and the SunOS
kernel is used to schedule all application threads. As a result, a
SPARC system running Solaris 10 serves out Apache webserver
requests much faster than on Linux. Additionally, Sun focuses on
high performance computing whereas the main function of the Linux
kernel is portability, ease of use etc. A must read for
all to understand what makes Solaris one of the best commercial UNIXes
on earth: http://www.sun.com/software/whitepapers/solaris9/multithread.pdf

To
be precise, on a non-SMP system, there isn't much to choose from
between Linux and OpenSolaris. But, once you start scaling to multiple
processors heavily, the difference between Linux and Solaris
(OpenSolaris included), is apparent. Solaris wins hands down! It is the killer OS for serious people!